Various cardiovascular procedures, such as angioplasty, stent placement and atherectomy, among others, are performed by inserting into and manipulating within the vasculature, wires and catheters adapted to perform those procedures. Access to the vasculature typically is through the femoral artery and is percutaneous, involving insertion of a needle in the region of the groin to form a track and to puncture and create an arteriotomy in the femoral artery. A guidewire then is advanced through the needle and into the femoral artery. The needle then is removed. An introducer sheath is then advanced over the guidewire. The wire and sheath provide access into the femoral artery, through the arteriotomy, for catheters or other instrumentalities in order to perform the selected procedure.
After the procedure has been completed, the procedural devices are removed and the arteriotomy must be closed. A number of techniques are known to facilitate closure and healing of the arteriotomy. These include application of pressure at the puncture site for a relatively extended length of time or the use of biological adhesives or plugs adapted to seal the arteriotomy, among others. Also among the techniques for closing the arteriotomy is the use of a staple system such as described in U.S. Pat. Nos. 6,506,210, 6,767,356 and 7,074,232 to Kanner et al., of which the disclosures of the devices and methods are hereby incorporated by reference. The Kanner patents described a system by which the original introducer sheath is removed, leaving the guidewire in place. Then, an assembly that includes a closure sheath and dilator is advanced along the indwelling guidewire to bring the distal end of the closure sheath into proximity to the outer surface of the arteriotomy. The closure sheath also carries an arrangement of display extending, wire-like stabilizers that, together with the dilator, pass through the arteriotomy into the artery.
The free ends of the stabilizers extend beyond the distal end of the closure sheath and are retained within pockets formed in the sides of the dilator to prevent the ends from interfering with advancement of the dilator or closure sheath through tissue.
The system enables the portions of the stabilizer wires, once disposed within the artery, to be formed into a temporarily enlarged shape that prevents removal of the stabilizer wires through the arteriotomy. The stabilizers and distal end of the closure sheath then are drawn together to grip the tissue about the arteriotomy and thereby secure and fix the position of the distal end of the sheath over and in alignment with the arteriotomy. The dilator and guidewire then are removed through the closure sheath, leaving the sheath in place adjacent the outer surface of the artery with the stabilizers within the artery, holding the sheath in place in readiness to provides direct access to the arteriotomy.
An arteriotomy closure device, such as a catheter-like stapler, with a staple carried in its distal end, then is inserted into and advanced through the closure sheath to located the staple in proximity to the arteriotomy. As described more fully in the Kanner patents, the sheath and stabilizer mechanisms orient the staple in registry with and at a fixed distance from the arteriotomy. When the stapler is actuated, the prongs of the staple expand and advance toward and into the arterial wall and surrounding tissue on opposite sides of the arteriotomy. The stapling mechanism then draws the prongs of the staple together to draw the edges of the arteriotomy together into approximation and then releases the staple. The stabilizers are caused to return to a linear shape, enabling their withdrawal. With the staple deployed and having closed the arteriotomy, the stapling mechanism and sheath may be removed, leaving the staple in place.
The dilator described in Kanner U.S. Pat. No. 6,767,356 is circular and has four separate lumens, including a guidewire lumen, a blood marking lumen, and a pair of side lumens. The distal ends of the side lumens server as pockets to temporarily receive the distal ends of the stabilizers when the dilator and closure sheath are advanced through tissue. The dilator includes side port openings in it sides, just beyond the distal end of the sheath, through which the distal ends of the stabilizers can be placed within the pockets. The portions of the side lumens proximal of the side ports, although useful in forming the stabilizer pockets, performed no function during operation or use of the system. It would be desirable, therefore, to provide a dilator for use in the arteriotomy closure system that omitted the proximal side lumens. The resulting dilator thus could have a lower profile or, alternatively, would enable the dilator or closure sheath to be further modified to include other operating functions and elements.